A recent study by Dr. Jinesh Kochar, a member of the
Gerontology Division at BIDMC, now suggests that eating
whole-grain cereal for breakfast could reduce the risk of developing high blood pressure in middle aged men. Dr. Kochar presented his research earlier this spring during a meeting of the American Heart Association. In this interview with HeartMail's research correspondent, Bonnie Prescott, he explains these findings and their possible implications.

Your study found that men had a reduced risk of developing high blood pressure if they ate whole-grain breakfast cereal every day. Can you briefly describe how the research was conducted?

This study analyzed data from the Physicians Health Study, which is a group of 13,368 U.S. male physicians who have been followed by researchers since 1982. These men periodically respond to detailed questionnaires about their health, and over the years, researchers have followed their development of various diseases, including
hypertension,
heart attacks and
heart failure. As a result, this large group of individuals has enabled medical researchers to better understand the impact of various lifestyle factors on a person's health.

For our particular research, we analyzed 16 years' worth of data regarding the men's dietary patterns. (The average age of the participants was 53 when data collection began.) None of the participants had high blood pressure when the study started; 7,267 men developed hypertension during this time period.

What did your research find?

We found that the participants who ate seven or more servings of whole-grain cereals per week had a 20 percent lower risk of developing hypertension, compared to participants who never (or rarely) ate whole-grain cereal. The men who ate two to six servings per week had a 13 percent lower risk of hypertension, and men who consumed at least one serving of whole-grain cereal each week had an 11 percent lower risk. (The authors arrived at these conclusions after adjusting for a number of "variable" factors, including age, alcohol consumption, intake of
fruits and vegetables, physical activity level, whether or not they
smoked and whether or not they had
diabetes.)

How do you think this might be happening?

Because we saw a statistically significant decrease in the risk of developing hypertension in the study participants who ate whole-grain breakfast cereal-but not in those who ate refined-grain breakfast cereals-we think the whole grains must play a role, but we don't know exactly how. We do know that some smaller studies (conducted in both laboratory animals and in human volunteers) have suggested that whole grains decrease the dangerous effects that "bad fats" can have on the endothelium (the inner lining of blood vessels).

Other ways that whole-grain cereals may be lowering blood pressure could be through magnesium, potassium or fiber. Whole-grain cereal may also improve insulin sensitivity.

What exactly is a whole-grain cereal? And how can you tell if your cereal is made with whole grains?

Whole grains such as wheat, oat, barley and maize contain three main structural components: the outer covering (bran or husk), the germ (which, when a seed grows, forms the body of the plant), and the endosperm (which is the bulk of the body of the grain, needed for the growing germ). Refined grain cereals, on the other hand, are mainly composed of only the endosperm. Although the content may vary, the cereal-box labels generally indicate if a cereal is made with whole grains.

Could it be that people who eat whole-grain cereal are healthier in general?

It is a possibility. However, it should be noted that all the study participants were generally healthy U.S. male physicians at the beginning of the study, and we saw a significant decrease in risk of hypertension, in a dose-response manner even after accounting for the effects of age, smoking,
alcohol consumption, fruit and vegetable intake, level of physical activity and diabetes.

Does eating whole-grain cereal have other positive health benefits in addition to lowering the risk of high blood pressure?

There is evidence that whole-grain cereals may protect against other chronic diseases, including diabetes and heart failure.